Toluene → benzyl 4'-oxo-6'-(pyridin-4-yl)-3',4'-dihydro-1'H-spiro[piperidine-4,2'-thieno[3,2-d]pyrimidine]-1-carboxylate

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Reaction Conditions

Reaction Steps

A mixture of 3-amino-5-(pyridin-4-yl)thiophene-2-carboxamide (0.219 g, 1.00 mmol), benzyl 4-oxo-1-piperidinecarboxylate (0.700 g, 3.00 mmol), p-toluenesulfonic acid monohydrate (0.211 g, 1.10 mmol) and toluene (10.0 mL) was stirred for 2 h at 90° C. Then, acetic acid (10.0 mL) was added, and the mixture was stirred for 1 h at 80° C. After removal of the solvent at reduced pressure, the obtained residue was poured into aqueous sodium hydrogen carbonate (200 mL). Extraction with ethyl acetate (200 mL, 100 mL), drying over magnesium sulfate, filtration and concentration at reduced pressure gave a solid. The solid was triturated with ethyl acetate/dichloromethane (1:1, 10 mL), and the precipitate was collected by filtration to afford the title compound (0.276 g, 64%) as a yellow solid:

Provenance & Evidence